Roads and highways have curb inlets to allow storm water to run off from the road into the storm drain or sewer and into a water retention area, a body of water or a processing facility.
Trash, leaves, debris, oil and other pollutants that flow into the storm drain system through the curb inlet or other means can lead to the pollution of waterways and contribute to flooding when they clog storm drain systems. Therefore, it is important to prevent pollutants from entering the storm drain system. To prevent pollutants from entering the storm drain system, a filter is placed at the storm water curb inlet in order to filter the water passing through the curb inlet. The present filter is designed so that it does not clog, even after accumulating lots of trash and debris. It is also made so that it does not bend inward when trash and debris accumulate; therefore, it does not allow trash and debris to enter the storm water drainage system.
U.S. Pat. No. 5,403,474 to Emery discloses a curb inlet gravel sediment filter. This type of filter may cause an obstruction to streets and is susceptible to tampering and damage from vehicles. Also, the mesh material can easily clog with debris—thereby reducing the effectiveness of the filter and contributing to flooding.
U.S. Pat. No. 7,563,364 to Shaw, et al discloses a modular curb inlet filter apparatus having an internal axial tube member on which are disposed at least two disc spacers, which in turn support a cylindrical mesh frame member, which in turn supports a tubular filter fabric. Since the filter uses a filter fabric on the outside, small particles can clog the filter and prevent water from entering the drain system. This can contribute to flooding, and the filter also requires frequent maintenance.
There remains a need for improved systems for filtering materials that pass through a drain system. Existing filters are clogged when they are filled with pollutants, and this can contribute to flooding. Filters with overflow mechanisms eventually lead to clogging because the overflow mechanisms do not properly filter pollutants that will enter the drain system.
It is desirable to have an efficient and cost-effective filter that can be placed at the street curb inlet, so that water can flow into the drainage system with fewer pollutants, without causing the drain or sewer system to clog, and without obstructing streets. The filter itself also needs to operate without clogging.